Plastic lunch box

ABSTRACT

A plastic lunch box is disclosed that includes a tray including a raised, flat bottom wall, a raised, staged edge including a lower first shelf, an upper second shelf of inverted U-section, and a bent intermediate section interconnecting the first and second shelves, and a substantially L-shaped member interconnecting the bottom wall and the edge; and a cover including a closed inner groove on a top, a raised top wall defined by the inner groove, an edge of inverted-U section, and a closed outer groove proximate the edge; whereby snapping the cover onto the tray will securely engage the outer groove with an upper portion of the intermediate section and securely engage the edge of the cover with the second shelf. The lunch box has a sufficient structural strength and can be manufactured in a cost effective process.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to food-carrying cases and more particularly to a lunch box formed of plastic having a sufficient structural strength by furrowing its edges, etc. and manufactured in a cost effective process.

2. Related Art

A conventional lunch box is formed of plastic, sheet metal, or paper. For manufacturing paper lunch boxes, precious wood resources may be consumed undesirably. Also, its cost is relatively high. For metal lunch boxes, they have a sufficient structural strength to endure repeated use for a long time. However, its cost is also relatively high. For plastic lunch boxes, typically they do not have a sufficient structural strength for the purpose of saving cost since the cost of manufacturing thick lunch boxes is higher than that of manufacturing thin ones. It is thus often found that a plastic lunch box deforms only after a very short period time of use. This is not desirable. Hence, a need has arisen for an improved plastic lunch box without the above inadequacy of the prior art.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a lunch box formed of plastic having a sufficient structural strength by furrowing its edges, etc. and manufactured in a cost effective process.

To achieve the above and other objects, the present invention provides a plastic lunch box comprising a tray including a raised, flat bottom wall, a raised, staged edge including a lower first shelf, an upper second shelf of inverted U-section, and a bent intermediate section interconnecting the first and second shelves, and a substantially L-shaped member interconnecting the bottom wall and the edge; and a cover including a closed inner groove on a top, a raised top wall defined by the inner groove, an edge of inverted-U section, and a closed outer groove proximate the edge; whereby snapping the cover onto the tray will securely engage the outer groove with an upper portion of the intermediate section and securely engage the edge of the cover with the second shelf.

In one aspect of the present invention each of the cover and the tray is of substantially rectangular.

In another aspect of the present invention each of the top wall and the bottom wall is of substantially rectangular.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of plastic lunch box according to the invention with a cover removed;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is a perspective view of a cover of the lunch box;

FIG. 4 is a sectional view taken along line B-B of FIG. 3; and

FIG. 5 is a perspective view of the assembled lunch box.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 to 5, a plastic lunch box in accordance with a preferred embodiment of the invention comprises a substantially rectangular tray 1 and a substantially rectangular cover 2. Each component is discussed in detailed below.

As shown in FIGS. 1 and 2, the tray 1 comprises a raised, flat bottom wall 16 of substantially rectangular, a raised, staged, closed frame 14 along an upper edge, and a substantially L-shaped member 15 interconnecting the bottom wall 16 and the frame 14. The frame 14 comprises a lower first shelf 11, an upper second shelf 13 of inverted U-section, and a bent intermediate section 12 interconnecting the first and second shelves 11 and 13. By configuring as above, structural strengths of both the edge and the bottom of the tray 1 are greatly increased. As a result, the tray 1 has a sufficient structural strength.

As shown in FIGS. 3 and 4, the cover 2 comprises a raised top wall 21 of substantially rectangular, a closed inner groove 22 for defining the top wall 21 therein, and a closed outer groove 23 proximate a closed edge of inverted-U section. By configuring as above, structural strengths of both the edge and the top wall of the cover 2 are greatly increased. As a result, the cover 2 has a sufficient structural strength. The cover 2 is dimensioned and shaped to fit snugly onto the tray 1 by snapping in which the outer groove 23 is fitted onto an upper portion of the intermediate section 12 besides the second shelf 13 with the second shelf 13 matingly received in a cavity formed by the edge of the cover 2. Thus, the edge of the tray 1 is sealably engaged with that of the cover 2. As an end, the lunch box has a sufficient structural strength. It is contemplated by the invention that thickness of the lunch box can be decreased further for saving the manufacturing cost since the lunch box has a sufficient structural strength as tested in a strength test.

While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims. 

1. A plastic lunch box comprising: a tray including a raised, flat bottom wall, a raised, staged edge including a lower first shelf, an upper second shelf of inverted U-section, and a bent intermediate section interconnecting the first and second shelves, and a substantially L-shaped member interconnecting the bottom wall and the edge; and a cover including a closed inner groove on a top, a raised top wall defined by the inner groove, an edge of inverted-U section, and a closed outer groove proximate the edge; whereby snapping the cover onto the tray will securely engage the outer groove with an upper portion of the intermediate section and securely engage the edge of the cover with the second shelf.
 2. The plastic lunch box of claim 1, wherein the cover is of substantially rectangular.
 3. The plastic lunch box of claim 1, wherein the tray is of substantially rectangular.
 4. The plastic lunch box of claim 1, wherein the bottom wall is of substantially rectangular.
 5. The plastic lunch box of claim 1, wherein the top wall is of substantially rectangular. 